Nasal Fungal Balls: Etiology, Diagnosis, and Management – An Expert Review

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Nasal Fungal Balls: Etiology, Diagnosis, and Management – An Expert Review

Introduction

Nasal fungal balls, also referred to as fungal mycetomas of the paranasal sinuses, are a non-invasive form of fungal sinusitis characterized by dense, matted fungal hyphae accumulating within a sinus cavity, most frequently the maxillary sinus. Although often asymptomatic, these lesions can lead to chronic sinonasal symptoms and are occasionally discovered incidentally during imaging for unrelated conditions. Early recognition is crucial, as untreated cases may progress to more aggressive fungal infections in immunocompromised individuals.

Etiology and Cause

Nasal fungal balls are typically caused by saprophytic fungi, most commonly Aspergillus fumigatus. The pathogenesis is believed to involve:

  • Impaired sinus drainage leading to fungal colonization

  • Pre-existing sinonasal anatomical variations

  • Chronic mucosal inflammation

  • Prior dental procedures introduced foreign material into the sinus cavity

Unlike invasive fungal sinusitis, nasal fungal balls do not invade the mucosa or surrounding bone.

Pathophysiology

The formation of a nasal fungal ball involves:

  1. Fungal spores enter the nasal cavity via inhalation.

  2. Mucociliary clearance impairment due to sinus ostium obstruction or mucosal inflammation.

  3. Accumulation of fungal hyphae forming a dense, matted mass.

  4. Deposition of calcium salts and heavy metals within the fungal mat, giving it characteristic hyperattenuation on CT imaging.

Importantly, the host’s immune system remains intact in most patients, preventing tissue invasion.

Epidemiology

  • Age: More common in older adults (6th to 8th decades)

  • Gender: Slight female predominance in some studies, though the case here involves an 80-year-old male

  • Geography: Higher incidence in warm, humid climates.

  • Risk Factors:

    • Prior dental work (e.g., root canal)

    • Chronic rhinosinusitis

    • Structural sinonasal abnormalities

Clinical Presentation

Most patients present with:

  • Chronic unilateral nasal obstruction

  • Facial pain or pressure

  • Postnasal drip

  • Hyposmia (reduced smell)

  • Occasionally asymptomatic, with diagnosis made incidentally on imaging, as in the present case

In our case:

Patient: 80-year-old male
Presentation: Decreased conscious state (incidental finding during workup)

Imaging Features

CT imaging is the gold standard for diagnosing nasal fungal balls.

  • Axial non-contrast CT: Multiple high-attenuation rounded lesions in the nasal cavity (Figure 1).

  • Sagittal non-contrast CT: Visualization of high-density material in the right maxillary antrum (Figure 2).

  • Coronal bone window CT: Hyperdense bubbly opacities with associated subcentimeter right ethmoid ivory osteoma (Figure 3).

Characteristic Imaging Signs:

  • Unilateral sinus opacification

  • Central hyperattenuation due to mineral deposition

  • No bony erosion (differentiating from invasive fungal sinusitis)

Figures

Figure 1: Axial non-contrast CT showing multiple high-attenuation rounded lesions within the nasal cavity.
Figure 2: Sagittal non-contrast CT demonstrating high-density bubbly material in the right maxillary antrum.

Figure 3: Coronal bone window CT highlighting a subcentimeter right ethmoid ivory osteoma adjacent to the fungal ball.

Differential Diagnosis

  • Chronic bacterial sinusitis

  • Allergic fungal sinusitis

  • Antrochoanal polyp

  • Sinonasal neoplasm with calcifications

Treatment

Primary treatment: Functional Endoscopic Sinus Surgery (FESS) with complete removal of the fungal ball and restoration of sinus drainage.

  • No systemic antifungal therapy is typically required in immunocompetent patients.

  • Postoperative care involves saline irrigations and monitoring for recurrence.

Prognosis

  • Excellent prognosis with complete surgical removal.

  • Recurrence is rare but can occur if fungal material is incompletely removed or drainage pathways remain obstructed.

  • No risk of systemic dissemination in immunocompetent patients.

Conclusion

Nasal fungal balls are a distinct, non-invasive form of fungal sinusitis with characteristic imaging features. Awareness of their presentation and imaging hallmarks allows for prompt diagnosis and treatment, preventing potential complications.

Quiz Section

1. Which fungus is most commonly associated with nasal fungal balls?
A) Candida albicans
B) Aspergillus fumigatus
C) Mucor species
D) Cryptococcus neoformans

2. What is the key imaging feature of nasal fungal balls on CT?
A) Bilateral sinus opacification with low density
B) Unilateral sinus opacification with central hyperattenuation
C) Diffuse mucosal thickening
D) Complete bone destruction

3. What is the first-line treatment for nasal fungal balls?
A) Oral antifungal medication
B) IV antibiotics
C) Functional Endoscopic Sinus Surgery (FESS)
D) Watchful waiting

Answer & Explanation

1. Answer: B) Aspergillus fumigatus. Explanation: Aspergillus fumigatus is the most frequently identified organism in nasal fungal balls, particularly in non-invasive forms.

2. Answer: B) Unilateral sinus opacification with central hyperattenuation. Explanation: The hyperattenuation is due to calcium and heavy metal deposition within the fungal mass.

3. Answer: C) Functional Endoscopic Sinus Surgery (FESS). Explanation: Surgery is required to physically remove the fungal ball; antifungals are not needed in immunocompetent patients.

References

[1] J. Klossek et al., “Functional endoscopic sinus surgery and fungal balls of the paranasal sinuses,” Laryngoscope, vol. 107, no. 1, pp. 112–117, 1997.
[2] A. Grosjean and M. Weber, “Fungal sinusitis: A review,” Eur Arch Otorhinolaryngol, vol. 264, pp. 461–470, 2007.
[3] C. Dufour et al., “Computed tomography of paranasal sinus fungal balls,” Eur Radiol, vol. 15, pp. 1934–1938, 2005.
[4] N. A. Ferguson, “Definitions of fungal rhinosinusitis,” Otolaryngol Clin North Am, vol. 33, no. 2, pp. 227–235, 2000.
[5] S. Nicolai et al., “Surgical treatment of fungal sinusitis,” Am J Rhinol, vol. 23, no. 5, pp. 473–478, 2009.
[6] D. Stammberger, “FESS for fungal sinusitis,” Ann Otol Rhinol Laryngol, vol. 94, pp. 336–340, 1985.
[7] M. deShazo et al., “Fungal sinusitis,” N Engl J Med, vol. 337, no. 4, pp. 254–259, 1997.

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